2 Channel Set-Up with Sub - question-been a while

Discussion in 'AV Receivers' started by Joe_Papeo, Feb 16, 2004.

  1. Joe_Papeo

    Joe_Papeo Stunt Coordinator

    Joined:
    Jan 1, 2001
    Messages:
    65
    Likes Received:
    0
    Edit:
    Can someone just tell me how to hook up a passive sub?

    I know i have 2 options. One piggybacking my speakers and the other using an external amp.

    Can someone tell me how to hook it up right?




    Original:
    So I am setting up my DJ equipment and until I find a new receiver, I am using some bookshelf system from college.

    I bought 2 JBL N Series bookshelves to use and I have a Sony Passive sub as well.

    So I am trying to set it up with the sub since the JBLs are 2 way, but its been so long since I set up a passive sub that I think I forgot how.

    I have the left speaker wire out from the receiver into the sub. Then from the sub into the left speaker, with both wires piggy backed.

    The right wire from the receiver directly into the right speaker.

    It sounds like garbage. Am I doing something wrong?
     
  2. Jesse Sharrow

    Jesse Sharrow Supporting Actor

    Joined:
    Jul 11, 2003
    Messages:
    745
    Likes Received:
    0
    You will need some sort of power for the passive sub. I think you need an extra channel on receiver... wont work in your case. Or you need a seperate amp.
     
  3. Joe_Papeo

    Joe_Papeo Stunt Coordinator

    Joined:
    Jan 1, 2001
    Messages:
    65
    Likes Received:
    0
    For some reason I remember piggybacking off of the left speaker connection when I had a pro-logic system.

    If I buy a decent 2 channel amp, will there be some way to connect a passive sub?

    If I buy a powered sub can I hook that up to a Denon 2 channel receiver? Is there a discrete sub out on a 2 channel set-up?
     
  4. JohnSer

    JohnSer Stunt Coordinator

    Joined:
    Dec 4, 2002
    Messages:
    198
    Likes Received:
    0
    Haven't touched a passive sub in quite awhile, but when I did, both left and right channels had an in and a out. The driver within the cabinet was a dual voice coil unit. The crossovers usually consist of a iron core inductor in series with the sub and a single cap in series with the main speakers. How many terminals on the back of the sub cabinet? Any labels on them?
     
  5. Joe_Papeo

    Joe_Papeo Stunt Coordinator

    Joined:
    Jan 1, 2001
    Messages:
    65
    Likes Received:
    0
    from what i remember, the only connections on my sub are a red/black speaker connection.
     
  6. Paul Spencer

    Paul Spencer Stunt Coordinator

    Joined:
    Sep 15, 2003
    Messages:
    159
    Likes Received:
    0
    If you do a passive sub, the efficiency will probably be so much less that you would have to mess with the crossover of the other speakers to get a match, or leave the bass as being weak and not able to keep up.

    You would be better off using a plate amp for the sub. You can hook it up to any amp provided that it either has a subwoofer pre-out like a HT receiver or the plate amp has high level inputs. Parts express has a tutorial on this.
     
  7. Joe_Papeo

    Joe_Papeo Stunt Coordinator

    Joined:
    Jan 1, 2001
    Messages:
    65
    Likes Received:
    0
    2 channel receiver dont have somewhere to connect a sub? i ask only because i am looking to buy a denon 2 channel.
     
  8. Paul Spencer

    Paul Spencer Stunt Coordinator

    Joined:
    Sep 15, 2003
    Messages:
    159
    Likes Received:
    0
    Joe,

    Not usually, they assume that you will only want a sub for movies, thus the "line out" only usually comes with AV receivers. If you find a stereo amp with a sub output, it will be rare. One thing you may find on a stereo amp is pre-outs. If you find that, then you can send that signal to the line in on a subwoofer plate amp. But if you use a sub plate amp with "high level inputs" which most of them have, then you can hook the sub up to any amp.

    Check out this link:

    Parts Express subwoofer FAQ - it will answer some of your questions and help you decide what to do and how to do it
     
  9. Robert_Gaither

    Robert_Gaither Screenwriter

    Joined:
    Mar 12, 2002
    Messages:
    1,370
    Likes Received:
    0
    Get something like the promedia for a pre-amp and get yourself either a 3 channel amp, 2 stereo amps, AVR with 5.1 inputs, or 2 channels of amplification/with a plate amp. If you do intend to DJ with them I advise to stick to small venues if possible.
     
  10. Paul Spencer

    Paul Spencer Stunt Coordinator

    Joined:
    Sep 15, 2003
    Messages:
    159
    Likes Received:
    0
    Robert,
    Any reason for suggesting this setup in preference to simple adding a plate amp? You have suggested a surround processor but the simplest way is to just add a plate amp, this is all he needs.

    Joe,
    The reason it sounds terrible is probably that you are running the sub fullrange. This is never a good idea. You need a filter to roll off above 120 Hz at the highest, if not 40 Hz or somewhere in between. This feature is provided by means of a variable crossover control on any plate amp.

    If you try to drive a subwoofer with the same amp as you use for your mains, you aren't really using a subwoofer as such, you are turning your 2 way speakers into 3 way, and to do that you must choose a crossover point and you have to consider the efficiency of the woofer and the other drivers. You may not have enough efficiency. This is why it is usually better to use an active subwoofer.
     

Share This Page